The greatest bending moment is at the bottom of the gin pole where it
attaches to the tower, not in the center.
On Thu, May 30, 2013 at 9:30 PM, Patrick Greenlee
<patrick_g@windstream.net>wrote:
> A good friend who has MS in mech engineering and 35+ years of hands on
> experience made the following suggestion to me:
>
> Do not splice the pole in the center where the greatest bending moment is.
> Add the extra material near the ends. In your case that would require you
> to cut one of your poles in half and add the pieces on either end of the
> uncut pole. If able, you may want to consider making the connecting piece
> fit over your poles rather than inside. That would be significantly
> stronger.
>
> Just food for thought. YMMV
>
> Patrick AF5CK
>
> -----Original Message----- From: K8RI
> Sent: Thursday, May 30, 2013 4:13 PM
> To: towertalk@contesting.com
> Subject: Re: [TowerTalk] A quest about Gin Poles
>
>
> On 5/30/2013 4:50 PM, Kevin Elliott wrote:
>
>> I have purchased all of the item to build my gin pole but I have one
>> question I am hoping someone can answer. I have two seven foot pieces of
>> 2" x .250"
>>
> aluminum that I am going to use for the gin pole itself. I also have a
> 6' length of 1.750" aluminum that I am going to use for the connector
> for the two 7' pieces.
> Now my question is this; how long should the 1.750" piece of aluminum
> be for the slice of the 2" pieces? I think having 3' in each of the 2"
> pieces is
> overkill and will add weight to the device. I was thinking more along
> the line of 4' section which allows 2' in each of the sections. Or
> should I go with 3' on each piece?
>
>>
>>
>>
> Having worked with these things for years, I wouldn't use a 2 piece gin
> pole except for very light work. 2nd I would consider the smaller
> inside splice to be too short. The first question is what alloy and
> temper is the tubing and splice?
>
> I use 12' and 24' sections of 6061T6 with 1/8th, 3/16 and 1/4 inch wall
> depending on the load.
>
> I would ask an engineer about the configuration you are planning.
>
> Climbing and using gin poles in tower work is quite dangerous!
> Every year we lose a number of well trained and experienced climbers.
> When something breaks up there your only thought is to get out of the
> way with out getting off the tower.
>
> Working on a 40 or 50 foot tower can be just as dangerous as working on
> the big ones. You are just working with smaller stuff which can be just
> as deadly as can a fall from that height.
>
> Be careful
>
> 73
>
> Roger (K8RI)
>
>
> Thanks
>> Kevin Elliott
>> KGXMN
>> kgXmn@kgXmn.com
>>
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